Field of the Invention
The invention relates to an arrangement for providing a land vehicle, in particular a rail vehicle or a road automobile, with electric energy. An electromagnetic field is produced on a primary side located on the track of the vehicle and/or located at a stop of the vehicle by a source (typically windings and/or coils of an electric conductor). The magnetic component of the electromagnetic field is received on a secondary side onboard the vehicle above the source of the electromagnetic field. By magnetic induction on the secondary side, the electric energy is produced. The invention also relates to a corresponding method of providing a land vehicle with electric energy. Furthermore, the invention relates to a land vehicle, in particular a rail vehicle or a road automobile, comprising the arrangement.
However, some but not all aspects of the present invention relate to a system which includes the primary side and the secondary side. Rather, one aspect of the invention only relates to the primary side and another aspect of the invention only relates to the secondary side.
The terms “primary side” and “secondary side” are used corresponding to the terminology which is used for transformers. In fact, the electric parts of a system for transferring electric energy from a vehicle track or from vehicles stop to the vehicle by induction (inductive power transfer system, in short: IPT system) form a kind of transformer. The only difference compared to a conventional transformer is the fact that the vehicle, and thus the secondary side, can move.
Description of Related Art
WO 2010/000495 A1 describes a system and method for transferring electric energy to a vehicle. The energy can be transferred to the vehicle while the vehicle is moving. While the present invention may relate to such a system, it is not restricted to the transfer of energy to moving vehicles. Rather, the energy maybe transferred while the vehicle temporarily stops (such as a bus at a bus stop) or while the vehicle is parked.
The vehicle may be any land vehicle, including track bound vehicles, such as conventional rail vehicles, mono-rail vehicles, trolley busses and vehicles which are guided on a track by other means. Other examples of land vehicles are road automobiles, including busses which are not track bound. For example, the vehicle may be a vehicle having an electrically operated propulsion motor. The vehicle may also be a vehicle having a hybrid propulsion system, e.g. a system which can be operated by electric energy or by other energy, such as electrochemically stored energy or fuel (e.g. natural gas, gasoline or petrol).
WO 2010/000495 A1 describes an example of serpentine windings on the primary side for producing the electromagnetic field. The primary side conductor assembly of the present invention, which is made of electrically conducting material that produces the electromagnetic field during operation while the electrically conducting material carries an alternating electric current, may have the same or a different configuration. In any case, at least sections and/or parts of the primary side conductor assembly has/have a length and a width, so that the primary side conductor assembly comprises lateral edges. For example, as described in WO 2010/000495 A1, sections of the primary side conductor assembly may extend along the track of the vehicle so that there are two lateral edges on opposite sides of the primary side conductor assembly. Other configurations are possible such as elongated electric conductors extending in the direction of travel, coils of electric conductors having several windings and arrangements of electric conductors having different configurations.
The features of a primary side conductor assembly which are described in the foregoing description may also apply to a secondary side conductor assembly, with the exception that this assembly is located on board the vehicle.
In any case, there is a gap between the primary side conductor assembly and the secondary side conductor assembly which causes emissions of the electromagnetic field, which is produced by the primary side conductor assembly, to the surroundings. In addition, an electric current flows through the secondary side conductor assembly during operation and this electric current also causes an electromagnetic field, which is denoted by “electromagnetic stray field” in the following. This stray field also causes emission of electromagnetic radiation to the surroundings.
Corresponding limit values, in particular of the electromagnetic or magnetic field strength, must be observed. In principle, the larger the gap between the primary side and the secondary side, the larger the field strength in the surroundings.